The tools help you test an idea using information you already have. They do not generate approved designs or predict what a contractor will charge.
Use the right inputs
Use internal dimensions for the space calculator, roof dimensions for the roof calculator and horizontal catchment area for rainwater. These areas answer different questions. Do not copy one result into another tool without checking that it measures what the next tool asks for.
Units and rounding
The measurement tools offer metric and imperial inputs. Switching units converts the dimensions already entered. Results are rounded for display; calculations use the underlying values. The rainwater tool labels US gallons explicitly. Insulation thickness remains in millimetres, as shown beside the field.
Prices and examples
Currency selection changes the label, not the exchange rate. All budget inputs must use the same currency. The budget example is invented to show how the worksheet adds costs; it is not a market estimate. Contingency applies to the project subtotal and excludes the separate land and tax lines.
Manufacturer data
The model comparison records basic specifications from the linked AVRAME product pages, checked on 16 September 2026. It uses the manufacturer’s stated floor area. The comparison is independent and carries no claim that a model is suitable or approved for your site.
Save and export
Calculations run in your browser. Save stores the current values locally on that device; it does not create an account or upload your planning notes. Export downloads a text copy. Reset removes the saved values for the tool you are using. Clearing browser data also removes saved values.
Every tool includes its formula and practical limits. Choose a planning tool →